201208170400 yc1pz

explained decrypted filler

3DES(name+title) ECB, 19 GUIDs, seed 606

Metadata

Post ID: yc1pz
Title: 201208170400 → 2012-08-17 04:00 on A858's clock
Posted (UTC): 2012-08-16 19:00:21
Timezone: UTC+9 · title 04:00 against posted 19:00 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 1,232 hex characters · 616 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9201208170400) = a2c2d136eedac4b9b1e161fb4f64526a (name+title)
New here: Missing from the community archive; decrypted here for the first time. (new results)
GUIDs: 19
Filler GUID seed: new Random(606).Next(9) ✓ verified
Run: Run 24 (seed 39,416,093) (seed)
Draw: 22 · predicted N = 19 ✓
Machine boot: 2012-08-15 10:18–10:21 (seed = uptime at app start)
Sources: arctic-shift · body from arctic-shift
Links: Reddit · Arctic Shift · JSON
Score · comments: 1 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listarctic-onlykey: name+titlerun: seed

From the post to its content

As posted (encrypted)

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

Read the ciphertext. Strip whitespace: 1,232 hex characters = 616 bytes = 77 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9201208170400 (name+title). Key = MD5(password) = a2c2d136eedac4b9b1e161fb4f64526a, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 19 GUIDs as hex (shown below).

Decrypted: GUID list

  1 9f23009a-0a4b-26d2-8ed6-0c42c98b38b0
  2 fa1a5585-81a1-50be-9df9-46b566848346
  3 fc7dcd71-e37f-353c-9b99-c37ddec00579
  4 6c5cb026-afc6-8f1f-8d80-60b6e97db071
  5 d5daad48-3654-78ce-b90f-6bb537e54f64
  6 973a2bc6-24f7-1be7-b602-537bb6402723
  7 8bd867b0-4359-3ec9-a847-b671304b3850
  8 22b8c162-d240-4c2d-b0f5-0951149bc65e
  9 f5c7e217-b75d-8d82-b03b-439d7488a35e
 10 afbc9882-f02f-64f2-9c26-daa0d4536ef0
 11 a65e2f2f-240f-6794-bf0a-e80c125ae749
 12 9123661d-5a63-5341-87cf-a33cdedac800
 13 1a970a11-b4c4-2bcb-8661-425daf22f161
 14 ced14ee6-3da8-67cd-a1f6-bfd2520cf7a8
 15 9dc9bfb5-eb67-1f8f-9d90-1d6313a488be
 16 112e9d10-89c8-4e51-a8cc-1aac1355b9b7
 17 2b3c02cd-d9d2-579c-a79a-106b5a57fa86
 18 d18c6148-e01a-6e41-a482-1f8fb2173a9a
 19 07160c8d-0644-043c-a021-66e81dbaa976

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 2538713486652614560. Exactly this sequence comes out of new Random(606).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID are Guid.NewGuid() output and carry no message.
Explain the count. This post is draw 22 of Run 24 (seed 39,416,093): new Random(39416093), Next(8,64) per post. The RNG predicts N = 19; the post has N = 19 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-08-15 10:18–10:21).
Conclusion. Filler. The content is fully explained by the two RNGs.

Metadata

From the post to its content

As posted (encrypted)

Decrypted: GUID list

Explanation

Related